The present invention relates to a semiconductor device. Embodiments of the invention provide a semiconductor device with at least two capacitors.
Capacitors are useful components which are used within many different electronic applications, e.g. for mixed-signal and analogue circuits. In modern semiconductor processes the metal-insulator-metal, MiM capacitor type has been especially developed so that it can be fabricated alongside other key semiconductor components, e.g. (without limitation) CMOS transistors, to allow complex circuits to be manufactured on silicon chip integrated circuits. The present specification includes several references to MiM capacitors, but it will be understood that the present invention also finds application with other types of capacitors.
In most semiconductor devices having two or more MiM capacitors the capacitors are made with one type and thickness of dielectric material sandwiched between two conductor layers. The choice of the layer dielectric material type and its thickness determines the capacitance density (capacitance per unit area) and the breakdown voltage value. Dielectric breakdown voltage limits the maximum voltage that a capacitor can withstand within a circuit. Thicker dielectrics are needed to obtain greater breakdown voltages. But thinner dielectrics have higher capacitance density, which allows the area of an individual capacitor to be made smaller.